Adhesive for bonding polyimide resins

Abstract

One embodiment relates to an, article and a method for producing an article including a plurality of substrates, and an adhesive bonded between at least two of the plurality of substrates. The adhesive can include a polycarbonate copolymer that includes reacted resorcinol, siloxane, and bisphenol-A. Another embodiment relates to an article having a first polyimide substrate, a second polyimide substrate, and an adhesive bonded between the first substrate and the second substrate. The article can have a 2 minute integrated heat release rate of less than or equal to 65 kilowatt−minutes per square meter (kW−min / m2) and a peak heat release rate of less than 65 kilowatts per square meter (kW / m2) as measured using the method of FAR F25.4, in accordance with Federal Aviation Regulation FAR 25.853(d).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of U.S. patent application Ser. No. 13 / 104,877, filed on May 10, 2011, which is hereby incorporated by reference in its entirety.FIELD OF THE INVENTION[0002]The invention relates generally to an adhesive for bonding polyimide resins, and more specifically to an adhesive comprising a polycarbonate copolymer comprising reacted resorcinol, siloxane, and bisphenol-A.BACKGROUND OF THE INVENTION[0003]Polyimide resins, such as those commercially available as ULTEM® brand resins, have excellent Flame, Smoke and Toxicity (FST) properties and mechanical properties and high temperature capability, but are difficult to bond and retain the FST requirements that are critical as for aircraft, marine and some rail applications. Bonding of sheets of polyimide foam for transportation applications or for radome construction where further machining and the retention of electrical properties such as uniform radar tra...

AI Technical Summary

Benefits of technology

This patent describes an adhesive made of a polycarbonate copolymer that includes resorcinol, siloxane, and bisphenol-A. This adhesive can be used to bond multiple substrates together, with the resulting article having low heat release rates and peak heat release rates. The adhesive can be made in different forms, such as a hot-melt adhesive, film, or fabric, and can be machined after bonding. Additionally, the patent also describes a method for bonding non-polyimide substrates or other materials together using this adhesive.

Problems solved by technology

Polyimide resins, such as those commercially available as ULTEM® brand resins, have excellent Flame, Smoke and Toxicity (FST) properties and mechanical properties and high temperature capability, but are difficult to bond and retain the FST requirements that are critical as for aircraft, marine and some rail applications.

Bonding of sheets of polyimide foam for transportation applications or for radome construction where further machining and the retention of electrical properties such as uniform radar transparency are important is also difficult.

Production of interior aircraft panels requires the application of decorative films over large areas, which requires additional time in the mold to develop a high strength bond for current adhesive systems adding time and cost to production, especially if the adhesive has a limited shelf-life.

Many of the existing adhesives require high temperature cures, degrade the flame, smoke and toxicity performance or produce a gummy line when additional machining is performed at the bond line.

There are a number of adhesives that can be used for bonding polyimideresin in its various forms, but many of those adhesives have only limited applicability since they fail to meet all but a few of the criteria.

Polyurethanes are highly effective adhesives but they give off toxic chemicals while burning.

Epoxies are similar to the polyurethanes in that they may provide excellent adhesion but epoxy adhesives can be very smoky and require extended cure time thus extending production time.

Epoxy adhesives also have limited shelf life and may require refrigerated storage.

Phenolic adhesives may provide very low fuel, but generally require high temperature cure and they have limited shelf life.

Any inconsistencies in electrical properties, such as inconsistent radar wave absorption, are problems that would have to be compensated for electronically or by use of additional devices.

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